These amazing patterns were spotted in the northern hemisphere of Mars on August 24, 2009 by the HiRISE camera aboard NASA’s orbiting Mars Reconnaissance Orbiter (MRO) spacecraft.
They are the tracks left by dust devils—mini tornadoes—moving across the Martian dunes.
Take a look at the high-resolution version (will open in a new window or tab) of the image—it’s quite amazing.
Dust devils form when the Sun heats the surface so that the ground is warm to the touch, even though the atmosphere at 2 metres (6 feet) above the surface would be chilly. That temperature contrast causes convection (rising air) to where the wind speed is slightly higher. Mixing the dust, winds, and convection triggers the dust devils.
Scientists use images of dust devils to study several things. Tracking the devils shows which way the wind blows at different times of day. Statistics on the size of typical dust devils will help with estimates of how much dust they pump into the atmosphere every day. And by watching individual devils change as they go over more-dusty and less-dusty terrain, researchers can learn about the turbulent motion near the surface. Ultimately, that motion of wind and dust near the surface relates these small dust devils with Mars’ much larger dust storms.
MRO was 285 kilometres above the Martian surface at the time it took the image, which shows detail down to about 1.7 metres resolution.
The video below shows the progress of a dust devil moving across the plains in full view of the Spirit lander. The sequence of images spans a period of 9 minutes and 35 seconds, but has been speeded up for the purposes of the video.
Adapted from information issued by NASA / JPL-Caltech / Cornell University / Texas A&M / University of Arizona.
Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz